The Price is Right!
I once read in a sailing magazine something like the following: “It’s boat show time, so let’s take a look at some of the products they are trying to foist on us poor unsuspecting boaters”. As a marine vendor I was incensed to read that, and vowed never to advertise in that publication. I never did, and eventually it folded. Go figure ....
There has long been a feeling that stuff sold for boats was generally overpriced simply because it has a “marine” tag. This seemed to be more prevalent in the 80’s and 90’s, so maybe back then there were indeed a plethora of cheap and tacky items labeled as marine that would have been better suited for the kiddies backyard camping or a day at the beach.
Or maybe it’s because nowadays the internet is playing devil’s advocate and unscrupulous manufacturers just can’t get away with things like they once could. Today’s efficient means of communication ensure that when even minor issues are reported, they require a good customer service oriented response.
Now that replacement parts can be easily sent to remote locations seemingly beyond the edge of beyond, a worthwhile warranty is also increasingly important. Imagine a business getting a call from a customer on a satellite phone in mid-ocean, fretting that his fridge is running longer than it used to. “We’ve got ourselves another fridge-fretting sat-phoner” is the common cry. Oh yeah, it happens.
At Coastal we see and hear many tales of woe
Solar by the Barrel-Load
There seems to be many misconceptions regarding solar panels, particularly concerning marine installations on vessels. I’m thinking that maybe it’s because we all see solar panels on houses and assume that what applies to roof-top installations also applies to boats. Wrong!
Here’s some solar facts. Typical solar panels with silicon cells will:
• Produce electrical power whenever they are exposed to light, and this is proportional. Small amount of light - small power output.
• Produce full voltage even in very low light, often even indoors, but only if they are disconnected and not being asked to produce any power. Potential voltage output depends mainly on the number of cells. Each cell typically produces around 0.6 to 0.7 volts.
• Produce full current output only if there is a big enough load, the sunlight is good enough, and shading is non-existent. Potential current output depends on the size and type of cells.
In general; the quantity of cells determines voltage; the quality of cells determines amperage.
Now, what we are after in a boat solar application is to grab whatever power we can whenever there is available sunlight, and that means from dawn right through to dusk, not just at noontime. I often hear customers say that there is absolutely no shading at the back of their sailboat, but then when it is suggested that maybe in early to mid morning or mid to late afternoon, the presence of a humongous mast and associated rigging might shade a stern-mounted panel, they will humbly agree. From that sort of response one could deduce that many boaters are under the assumption that solar panels will really only work for a couple of hours each side of noon. Not so Horatio.
AC/DC Controller: digging for answers
Once upon a time, a long time ago, there was only one brand of refrigerator that would work on 12v DC boat power. There must have been many thousands of them out there back in the day, predominately on powerboats, and a lot still exist to this day.
These refrigerators have one or two compressors typically mounted on the rear of the cabinet, and these compressors require 20v-30v AC for their operation. When 115v AC mains power is available, either from shore power or a generator, the power for the compressor(s) is supplied by using a simple transformer to lower the 115v AC down to the lower AC voltage required by the compressor(s).
But when the boat unplugs from the dock or the generator quits, the compressor is then powered from a built-in inverter that produces the required low voltage AC from the 12v DC supply. Due to losses inherent in inverters and the desire not to involve electronics unless absolutely necessary, these fridges would always be supplied with separate wiring for connection to both 115v AC and 12v DC, with the system automatically switching to 115v AC if it is available.
Fast forward to modern times, and we are now blessed to have marine fridges utilizing the super-efficient Secop (formally Danfoss) compressors that are powered by 12v or 24v DC. Under normal circumstances, when the vessel is at the dock and plugged in to shore power, the battery charger will be on and supplying the DC power for the fridge. The batteries are not involved in this process, as the DC from the charger does not go into and out of the batteries, but is supplied directly to the fridge from the charger.
In this situation there will always be 12v or 24v DC available, but if circumstances dictate that the charger will not be left on, or that at times there will be no 12v or 24v DC available,